When given 3 triangle sides, to determine if the triangle is acute, right or obtuse:
1) Square all 3 sides.
2) Sum the squares of the 2 shortest sides.
3) Compare this sum to the square of the 3rd side.
if sum > 3rd side² Acute Triangle
if sum = 3rd side² Right Triangle
<span>if sum < 3rd side² Obtuse Triangle
</span>
1) 144
<span>
<span>
<span>
1,225
</span>
</span>
</span>
1,369
144 + 1,225 = 1,369
Therefore, it is a right triangle.
Source:
http://www.1728.org/triantest.htm